Explosive operated switch for bomb fuzing system

ABSTRACT

This invention relates to an explosive type switching device and comprises a main explosive charge, means for causing the detonation of this main explosive charge in response to an electrical signal, a deformable diaphragm adapted to be deformed by the detonation of the explosive charge such that a shaft is projected forward from a first position to a second position in response to the deformation. The movement of said shaft causes the actuation and change of mode of at least two sets of fixed contacts. Movement of the shaft transposes at least one electrical contact member such that the first set is electrically connected to each other when said shaft is in the first position. Upon movement of the shaft the first set of fixed contacts are irreversibly disconnected from each other and the shaft moves the electrical contact member to a second position irreversibly connecting the second set of fixed contacts to each other through the contact member. The second set of contacts are located at a plane transverse to the plane of the first set of contacts.

United States Patent Apstein et al.

[ EXPLOSIVE OPERATED SWITCH FOR BOMB FUZING SYSTEM [72] Inventors: Maurice Apstein, Bethesda, Md.; Evert Blomgren, Kensington, Conn.; George R. Keehn, Washington, D.C.; Laurence M. Andrews, Silver Spring; Jacob Rabinow, Takoma Park, both of Md.

[73] Assignee: The United States of America as represented by the Secretary of the Army [22] Filed: May 26, 1969 [2]] App]. No.: 848,129

Related US. Application Data [62] Division of Ser. No. 555,216, Dec. 23, 1955.

[52] US. Cl. ..102/70.2 R, 200/83 R [51] Int. Cl ..F42b 5/08 [58] Field of Search ..200/83 R; 102/75, 70.2, 28

[56] References Cited UNITED STATES PATENTS 1,369,476 2/1921 Semple ..102/75 2,381,900 8/1945 Graumann et al 102/75 2,567,519 9/1951 Livingston ..200/83 R 2,575,071 11/1951 Rockwell ..89/1 H 2,721,240 10/1955 Filbert, Jr. ..200/83 R 2,921,525 1/1960 Ricker ..102/75 51 Oct. 17, 1972 FOREIGN PATENTS OR APPLICATIONS 520,626 3/1955 Italy ..200/83 R Primary Examiner-Samuel Feinberg Attorney-W. E. Thibodeau, A. W. Dew and .1. D. Edgerton [57] ABSTRACT This invention relates to an explosive type switching device and comprises a main explosive charge, means for causing the detonation 'of this main explosive charge in response to an electrical signal, a deformable diaphragm adapted to be deformed by the detonation of the explosive charge such that a shaft is projected forward from a first position to a second position in response to the deformation. The movement of said shaft causes the actuation and change of mode of at least two sets of fixed contacts. Movement of the shaft transposes at least one electrical contact member such that the first set is electrically connected to each other when said shaft is in the first position. Upon movement of the shaft the first set of fixed contacts are irreversibly disconnected from each other and the shaft moves the electrical contact member to a second position irreversibly connecting the second set of fixed contacts to each other through the contact member. The second set of contacts are located at a plane transverse to the plane of the first set of contacts.

3 Claims, 3 Drawing Figures PATENTEU 17 1973 3,698,323

BY; ciiz glizfwauz 4 g; A'ITORNEY5.

EXPLOSIVE OPERATED SWITCH FOR BOMB FUZING SYSTEM This application is a division of application Ser. No. 555,216, filed Dec.23, 1955.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to use of any royalty thereon.

This invention relates to explosive ordnance devices and more particularly to the fuzing of aircraft-released bombs. An important feature of the invention is the provision of a high-safety aircraft bomb fuzing system that enables a bombardier revocably to choose alternative fuzing characteristicse.g., various alternative arming delay times and impact delay times for a bomb at any time up to the instant of release of the bomb from an aircraft.

Typical aircraft-released bombs of the impact-fuzed type are fuzed so as to arm at a predetermined time after released and so as to explode on impact or at a predetermined time after impact. As is well known in the bombing art, the optimum arming delay and the optimum delay-after-impact depend on the nature of the tactical mission. For example, to minimize the danger to other bombing aircraft flying in formation it is desirable that the arming delay be such that arming occurs only after the bomb has fallen a considerable distance, though before it reaches its target. This means that low-level bombing requires shorter arming delays than are desirable for high-level bombing. Similarly, instantaneous detonation on impact is desirable in attacking thin or fragile targets, but progressively greater delays-after-impact may be desirable for targets requiring penetration before detonation and for other tactical purposes.

In the past, preparation for a bombing mission has typically entailed, first, a decision as to the most desirable arming delay and impact delay times for the particular mission. From such stocks of fuzes of various characteristics as may be on hand, fuzes having the most suitable characteristics available are then selected. One of these fuzes is then affixed individually to each bomb. The bombs are then loaded into the aircraft bomb bay. If for any reason it is then decided that different fuzing characteristics are desired, the bombs must in general be removed from the bomb bay for the substitution of different fuzes. Once the bomber is aloft it is generally impossible for the bombardier to change the fuzing characteristics to better adapt them to changed tactical situations that may develop. The logistical disadvantages of having to provide different fuzes for different tactical missions, and the tactical disadvantages of not being able to alter fuzing characteristics quickly and easily, are largely apparent.

A principal object of the present invention is to provide a highly safe aircraft bomb fuzing system that will permit the quick, easy, and reversible selection, from within the aircraft, of alternative bomb-fuzing characteristicse.g., of various alternative arming delay times and impact delay timesat any time up to the instant of release of a bomb from an aircraft.

Another object is to provide a multi-purpose bomb fuze, having readily selectable alternative arming times and impact delay times, adapted to replace a number of hitherto-needed different bomb fuzes and thus to simplify logistical problems.

Still another object is to provide a system, controllable from aboard an aircraft, for altering any of a number of characteristics of a bomb released from the aircraft.

Yet another object is to provide means for the remote setting of one or more characteristics of an explosive ordnance device.

A further object is to provide improved devices for accomplishing at least one irreversible electrical switching operation in response to an electrical actuating impulse.

Briefly, in a preferred embodiment of the invention release of the bomb from the aircraft is accompanied by the automatic application to the bomb for a short period as it starts downward, through an extensible and disconnectable single conductor extending from the interior of the aircraft to the bomb of (a) d-c energy that charges a power capacitor within the bomb and also, at the option of the bombardier, of (b) r-f energy of one or more frequencies that actuates irreversibly one or more frequency-sensitive switching devices within the bomb. These switching devices are adapted to alter resistance or capacitance values in resistancecapacitance arming-delay and impact-delay circuits, and thus to alter the arming delay and impact delay times. Instead of or in addition to actuating switching devices, the r-f energy may be utilized to actuate mechanical delay trains or other devices aboard the bomb. The bombardier, at any time prior to release of the bomb, is able manually to set appropriately calibrated arming-delay and impact-delay selector switches that determine which r-f frequencies will be applied to the bomb on release and that thus determine which of the frequency-responsive devices aboard the bomb will be actuated. Explosive-type switching devices of the novel construction are provided. Although the invention is applicable primarily to bomb fuzing, it will become apparent that the invention is also applicable to other ordnance devices.

Other objects, aspects, uses, and advantages of the invention will become apparent from the following detailed description and from the accompanying drawing, in which:

FIG. 1 is an axial section of a preferred explosive switch (in the unactuated condition) in accordance with the invention.

FIG. 2 is a partial axial section of the switch of FIG. 2 after actuation. The FIG. 3 axial section is taken at an angle of with respect to the FIG. 2 axial section.

FIG. 3 is an axial section of the explosive or motor end of a delayed-action explosive switch in accordance with the invention.

FIG. 1 shows a quick-acting explosive switch 143 in accordance with the invention, prior to actuation. The principal electrical elements are a first pair of metallic contact fingers 147a and 147b, a second pair of metallic contact fingers 148a and 148b, and a flared movable contact cup 155. In the unactuated position contact cup provides an electrical short-circuit between contacts 147a and 147b. Cup 155 is mounted on a shaft 166 of insulating material the other end of which is in contact with a soft metal deformable diaphragm member 165. On the other side of diaphragm member is a main charge of explosive material 162 in which is embedded a pair of electrical leads 159 shorted by a fine wire bridge 160 in contact with an ignition charge 161. Application of a suitable electrical signal to leads 159 causes the temperature of bridge 160 to rise sufficiently to ignite ignition charge 161, which in turn ignites main charge 162. The combustion of charge 162 produces a rapid leftward movement of deformable diaphragm member 165, shaft 166, and contact cup 155. This leftward movement causes cup 155 to unshort-circuit contact fingers 147a and 147b and to short-circuit contact fingers 148a and 14%.

Cup 155 preferably has a flare 156 that prevents premature leftward motion of cup 155 but that yields in response to the explosion of charge 162.

FIG. 2 shows the position of cup 155 after switch 143 has been actuated. Fingers 148a and l48b are located leftward of fingers 147a and 147b. The planes of the two pairs of fingers are preferably at right angles to each other.

It will be understood that additional fixed contacts and additional moving contacts may readily be provided within the scope of the invention.

FIG. 3 shows the rightward or motor end of a novel delayed-action explosive switch 169 in accordance with the invention. The leftward or electrical end of switch 169 may be similar to that of switch 143 shown in FIGS. 1 and 2.

In FIG. 3 means, which may consist of a pair of wire leads 168 shorted by a carbon bridge 170 which contacts an ignition charge 171, are provided for the rapid electrical ignition of a transverse layer of flash powder 172. Upon ignition, powder 172 promptly ignites the rightward end of a transverse layer of pyrotechnic delay powder 173 having appreciable thickness. An appreciable time, determined by the thickness and characteristics of delay powder 173, is required for the propagation of combustion from the rightward end to the leftward end of delay powder 173. A thin paper separator 174 and a perforated metal disc 175 at the leftward end of delay powder 173 help keep delay powder 173 properly positioned but permit the leftward propagation of flame and hot gases to ignite a main charge 162a that is in contact with deformable diaphragm 165a. It will thus be understood that there is a delay, determined principally by the thickness and combustion characteristics of delay powder 173, between the time at which an actuating impulse of electrical energy is applied to leads 168 and the time at which main charge 162a drives diaphragm 165a leftward to cause the performance of desired electrical switching operations.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

We claim:

1. An explosive-type switching device comprising a main explosive charge; means including an electrothermal element for causing the detonation of said main explosive charge in response to an electrical impulse; a deformable diaphragm adapted to be deformed by the detonation of said explosive charge; a shaft adapted to move axially from a first position to a second position in response to the deformation of said diaphragm; at

1 ast one electrical ontact member carried b said shaft; and at least a first and second set of fixed contacts, said fixed contacts of said first set being electrically connected to each other through said contact member when said shaft is in said first position and being irreversibly and electrically disconnected from each other when said shaft is in said second position and said fixed contacts of said second set being irreversibly and electrically connected to each other through said contact member when said shaft is in said second position, said second set of contacts being located in a plane perpendicular to the plane in which said first set of contacts are located, and wherein said electrical contact member carried by said shaft comprises a metallic cup surrounding the end portion of said shaft.

2. The invention as defined in claim 1 wherein said cup has a flared portion to prevent premature motion.

3. The invention as defined in claim 2 wherein said means for causing the detonation of said main explosive charge includes a pyrotechnic delay element interposed between said electrothermal element and said main explosive charge, for delaying the ignition of said main explosive charge by a time dependent upon the dimensions and combustion characteristics of said element, and which further comprises a paper separator and a perforated metal disc for maintaining said delay element properly positioned and for permitting the propagation of flame and hot gases to ignite said main charge. 

1. An explosive-type switching device comprising a main explosive charge; means including an electrothermal element for causing the detonation of said main explosive charge in response to an electrical impulse; a deformable diaphragm adapted to be deformed by the detonation of said explosive charge; a shaft adapted to move axially from a first position to a second position in response to the deformation of said diaphragm; at least one electrical contact member carried by said shaft; and at least a first and secOnd set of fixed contacts, said fixed contacts of said first set being electrically connected to each other through said contact member when said shaft is in said first position and being irreversibly and electrically disconnected from each other when said shaft is in said second position and said fixed contacts of said second set being irreversibly and electrically connected to each other through said contact member when said shaft is in said second position, said second set of contacts being located in a plane perpendicular to the plane in which said first set of contacts are located, and wherein said electrical contact member carried by said shaft comprises a metallic cup surrounding the end portion of said shaft.
 2. The invention as defined in claim 1 wherein said cup has a flared portion to prevent premature motion.
 3. The invention as defined in claim 2 wherein said means for causing the detonation of said main explosive charge includes a pyrotechnic delay element interposed between said electrothermal element and said main explosive charge, for delaying the ignition of said main explosive charge by a time dependent upon the dimensions and combustion characteristics of said element, and which further comprises a paper separator and a perforated metal disc for maintaining said delay element properly positioned and for permitting the propagation of flame and hot gases to ignite said main charge. 